Temperature control system for a fuel tank and a canister of a vehicle using an acoustic refrigerator

ABSTRACT

A temperature control system for a fuel tank and a canister of a vehicle includes: an acoustic refrigerator; a low temperature circulation line transmitting a low temperature circulation fluid cooled by the low temperature heat exchanging portion to the fuel tank; a low temperature heat exchanger installed within the fuel tank and connected to the low temperature circulation line so as to transfer heat within the fuel tank to the low temperature circulation fluid; a high temperature circulation line sending the high temperature circulation fluid heated by the high temperature heat exchanging portion to the canister; a high temperature heat exchanger installed to the canister and connected to the high temperature circulation line, so as to transfer heat of the high temperature circulation fluid to the canister; and a control unit controlling the acoustic refrigerator.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority to Korean Patent Application No. 10-2006-0052027 filed in the Korean Intellectual Property Office on Jun. 9, 2006, the disclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a temperature control system for a fuel tank and a canister of a vehicle. More particularly, the present invention relates to a temperature control system for a fuel tank and a canister of a vehicle with an acoustic refrigerator that utilizes thermoacoustic effect of heat transfer by an acoustic wave.

(b) Description of the Related Art

Generally, an acoustic wave is produced by the propagation of density vibration within a medium. When a tube with a solid outer surface is filled with gas, a vibration is propagated direction of gas medium by an acoustic wave, such density vibration, generates pressure pulsation.

The pressure pulse involves a temperature change according to adiabatic compression and adiabatic expansion of gas medium within the tube, and the transfer of heat in a direction opposite to the transfer direction of vibration of gas medium by an acoustic wave at the boundary surface of a solid body. This is referred to as a thermoacoustic effect. Inert gas such as helium, argon, and xenon, which is safe when it is released into the air, is generally used as the vibration transferring medium.

As shown in FIG. 1, an acoustic refrigerator includes an acoustic wave generator (for example, a speaker system) 1, a stack 2, a resonance tube 3, a high temperature heat exchanger 4, and a low temperature heat exchanger 5.

Electrical energy is supplied to the acoustic wave generator 1 from an electrical power source 6, thereby generating an acoustic wave. The generated acoustic wave is transferred to the resonance tube 3 through the stack 2. While the acoustic wave is transferred in a longitudinal direction of the resonance tube 3, heat of the gas medium that fills the resonance tube 3 is transferred to the stack in a direction opposite to the direction of the acoustic wave being transferring by the thermoacoustic effect.

The stack 2 takes the heat of the gas medium through the low temperature heat exchanger 5 and transfers the taken heat to the high temperature heat exchanger 4. Heat of the high temperature heat exchanger 4 is transferred to surrounding high temperature circulation fluid, and is then discharged to the outside. In contrast, heat of the low temperature heat exchanger 5 is transferred to a low temperature circulation fluid such as water or glycol, and is then discharged to the outside, thereby resulting in a cooling effect.

Similar to a cooling method used thermoelectric effect, the cooling method using the acoustic refrigerator is environmentally friendly when compared to a compression type cooling method. This is because it does not use coolant. This cooling method has various advantages such as, lower maintenance cost, less noise and vibration, more accurately control of temperature, and lower electric power consumption.

Meanwhile, if the temperature of fuel within the fuel tank of a vehicle increases, fuel is evaporated and evaporative gas from the fuel is generated. The evaporative gas from the fuel is mainly hydrocarbon (HC). The fuel evaporative gas fills an empty space of a fuel tank, and after fully filling the empty space of the fuel tank, the fuel evaporative gas escapes from the fuel tank.

Current vehicle emission regulations tightly limit an amount of hydrocarbon discharged from a vehicle. It is also necessary to limit evaporative gas from fuel discharge from a fuel tank in regard to fuel consumption. In order to achieve this, the vehicle is modified with the addition of a canister, which serves as storage space for collecting the evaporative gas generated in the fuel tank. The collected gas is sent to an intake pipe of an engine through a purge valve, and is then sent to a combustion chamber of an engine at a suitable timing so as to be burned.

In order to suppress generation of fuel evaporative gas, it is preferable that a fuel tank is cooled below a predetermined temperature. Meanwhile, since an amount of purge by the canister needs to be increased in order to prevent problems such as an engine stall by inflow of purge gas of high density in restart after stopping, the canister needs to be moderately heated.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide a temperature control system for a fuel tank and a canister of a vehicle having advantages of minimizing an amount of fuel evaporative gas by cooling an inner space of the fuel tank and increasing an amount of purge by heating a surface of the canister by using an acoustic refrigerator using a thermoacoustic effect.

An exemplary embodiment of the present invention provides a temperature control system for a fuel tank and a canister of a vehicle including: an acoustic refrigerator including an acoustic wave generator, a resonator filled with gas medium and converting an acoustic wave generated by the acoustic wave generator to a standing wave, a stack disposed between the acoustic wave generator and the resonator so as to transmit the acoustic wave to the resonator, a low temperature heat exchanging portion formed at an end portion of the stack toward the resonator so as to transfer heat depending on compression and expansion of gas medium, and a high temperature heat exchanging portion formed at an end portion of the stack toward the acoustic generator so as to receive the heat transferred from the low temperature heat exchanging portion; a low temperature circulation line one end of which is connected to the low temperature heat exchanging portion and the other end of which is connected to the fuel tank so as to transmit a low temperature circulation fluid cooled by the low temperature heat exchanging portion to the fuel tank; a low temperature heat exchanger installed within the fuel tank and connected to the low temperature circulation line so as to transfer heat within the fuel tank to the low temperature circulation fluid; a high temperature circulation line one end of which is connected to the high temperature heat exchanging portion and the other end of which is connected to the canister 20, so as to send the high temperature circulation fluid heated by the high temperature heat exchanging portion to the canister; a high temperature heat exchanger installed to the canister and connected to the high temperature circulation line, so as to transfer heat of the high temperature circulation fluid to the canister; and a control unit controlling the acoustic refrigerator.

The temperature control system for a fuel tank and a canister of a vehicle may further include a temperature sensor for detecting a temperature within the fuel tank and outputting a corresponding signal, and the control unit may control the acoustic refrigerator on the basis of the signal of the temperature sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an acoustic refrigerator.

FIG. 2 is a diagram of a temperature control system of a fuel tank and a canister using an acoustic refrigerator according to an embodiment of the present invention.

FIG. 3 is a graph showing the amount of purge produced by heating a canister in a temperature control system of FIG. 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

An exemplary embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings.

FIG. 2 is a diagram of a temperature control system of a fuel tank and a canister using an acoustic refrigerator according to an embodiment of the present invention. FIG. 3 is a graph showing an amount of purge produced by heating of a canister in a temperature control system of FIG. 2.

As shown in FIG. 2, a temperature control system S for a fuel tank and a canister of a vehicle using an acoustic refrigerator includes: a fuel tank 10 for storing fuel supplied to an engine E; a canister 20 for storing fuel evaporative gas generated in the fuel tank 10 and sending the fuel evaporative gas to the engine E; and an acoustic refrigerator 50, which utilizes thermoacoustic effect for cooling. The temperature control system S also includes a low temperature circulation line L and a high temperature circulation line H for performing heat exchange between the fuel tank 10 and the canister 20. The temperature control system S further includes a low temperature heat exchanger 60 and a high temperature heat exchanger 70 respectively for exchanging heat between the low temperature circulation line L and the fuel tank 10, and between the high temperature circulation line H and the canister 20. In addition, because the acoustic refrigerator 50 may be controlled according to a temperature of the fuel tank 10, the temperature control system may further include a temperature sensor 30 for monitoring a temperature within the fuel tank 10.

The acoustic refrigerator 50 includes an acoustic wave generator 52 that generates an acoustic wave, a resonator 54, a stack 56, a low temperature heat exchanging portion 58 formed at an end portion of the stack 56 toward the resonator 54 so as to transfer heat of gas medium, and a high temperature heat exchanging portion 59 formed at an end portion of the stack 56 toward the acoustic generator 52 so as to receive the heat transferred from the low temperature heat exchanging portion 58. The resonator 54 may be filled with a gas medium and converts the acoustic wave generated by the acoustic wave generator 52 to a standing wave. The stack 56 is disposed between the acoustic wave generator 52 and the resonator 56 so as to transmit the acoustic wave to the resonator 54. Since the acoustic refrigerator 50 can be realized as a conventional acoustic refrigerator, detailed explanations thereof will be omitted.

Fuel stored in the fuel tank 10 is evaporated according to an ambient temperature. The amount of evaporated fuel increases as the ambient temperature increases. Accordingly, the amount of evaporated fuel can be calculated on the basis of a measured temperature within the fuel tank.

The fuel tank 10 includes a temperature sensor 30 for measuring the temperature within the fuel tank 10. The temperature sensor 30 measures the temperature within the fuel tank 10 and outputs a temperature signal corresponding to the measured temperature to a control unit 40. The control unit 40 controls the acoustic refrigerator 50 on the basis of the temperature signal input from the temperature sensor 30.

If it is determined, on the basis of the temperature signal, that the temperature within the fuel tank 10 is higher than or equal to a specific temperature, the control unit 40 outputs a cooling control signal so as to operate the acoustic refrigerator 50. Gas medium, such as helium, argon, xenon, or any other suitable gas medium, fills the inner space of the resonator 54 and expands when the acoustic wave generator 52 of the acoustic refrigerator 50 operates to generate an acoustic wave.

While the acoustic wave is transferred in a longitudinal direction of the resonator 54, gas medium absorbs heat from surroundings so that the temperature of gas medium increases. During this process, heat of the gas medium is gradually transferred to the low temperature heat exchanging portion 58 coupled to an end of the stack 56.

Heat transferred to the low temperature heat exchanging portion 58 is transferred to the high temperature heat exchanging portion 59 through gas medium around the stack 56. The high temperature heat exchanging portion 59, which has been at a relatively low temperature, absorbs heat of the low temperature heat exchanging portion 58 that has been transferred to the stack 56.

One end of the low temperature circulation line L is connected to the low temperature heat exchanging portion 58, and the other end thereof is connected to the fuel tank 10. As a result, the low temperature circulation line L circulates low temperature circulation fluid around the low temperature heat exchanging portion 58 and is cooled.

The low temperature circulation fluid flowing within the low temperature circulating line L is sent to the low temperature heat exchanger 60 installed in the inside of the fuel tank 10. As a result, heat within the fuel tank 10 is transferred to the low temperature circulation fluid through the low temperature heat exchanger 60 and the temperature within the fuel tank 10 decreases. Accordingly, because the temperature within the fuel tank 10 decreases, the amount of evaporated fuel is decreased and generation of fuel evaporative gas is minimized.

The low temperature circulation fluid which has been heated by heat within the fuel tank 10 is sent to the acoustic refrigerator 50. The low temperature circulation fluid is again cooled while gas medium within the resonator 54 is compressed to absorb surrounding heat, and the low temperature circulation fluid is again used to cool the fuel tank 10.

Although the amount of evaporated fuel in the fuel tank 10 is decreased by the coolant, fuel evaporation is not completely stopped but is decreased. Accordingly, the generated fuel evaporative gas is discharged to the canister 20.

Meanwhile, heat transferred to the high temperature heat exchanging portion 59 from the low temperature heat exchanging portion 58 is transferred to the high temperature circulation fluid around the high temperature heat exchanging portion 59, and the heated high temperature circulation fluid is sent to the canister 20 through the high temperature circulation line H. One end of the high temperature circulation line H is connected to the high temperature heat exchanging portion 59 and the other end is connected to the canister 20.

The heated high temperature circulation fluid is sent to the high temperature heat exchanger 70 that is formed at a surface of the canister 20, and heat exchange occurs in the high temperature heat exchanger 70, so that heat of the high temperature circulation fluid is transferred to the canister 20 at a relatively low temperature.

The high temperature circulation fluid cooled by the heat transfer is sent to the acoustic refrigerator 50 and cools the surroundings of the high temperature heat exchanging portion 59 such that the temperature of the high temperature heat exchanging portion 59 becomes lower than the temperature of the low temperature heat exchanging portion 58. Accordingly, heat of the low temperature heat exchanging portion 58 is transferred to the high temperature heat exchanging portion 59, so that the high temperature circulation fluid is again heated and the heated high temperature circulation fluid is again used to heat the canister 20.

As shown in FIG. 3, if the fuel evaporative gas is supplied to an engine in a state that temperature of the fuel evaporative gas within the canister 20 is increased, an amount of purge is increased so as to enhance engine operation. Accordingly, since the fuel tank is not heated over a certain temperature, generation of excessive fuel evaporative gas can be prevented. In addition, since the canister can be maintained at a relevant temperature, an amount of purge can be increased so as to enhance engine performance.

While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

According to an embodiment of the present, the application of an acoustic refrigerator utilizing thermoacoustic effect, an inner space of the fuel tank is cooled so that an amount of fuel evaporative gas is minimized, and a surface of the canister is heated so that an amount of purge is increased.

Furthermore, regulations of fuel evaporative gas can be effectively coped with, and an excessive amount of purge does not need so that engine controllability is enhanced and an operating performance is improved.

Still furthermore, the value of an environmental friendly brand image may be increased because, according to one embodiment of the present, use a technology nonpolluting and environmental friendly the present invention can be easily applied to a hybrid vehicle or a fuel cell vehicle. 

1. A temperature control system for a fuel tank and a canister of a vehicle, comprising: an acoustic refrigerator comprising an acoustic wave generator, a resonator for converting an acoustic wave generated by the acoustic wave generator to a standing wave, a stack disposed between the acoustic wave generator and the resonator so asor to transmit the acoustic wave to the resonator, a low temperature heat exchanging portion formed at an end portion of the stack toward the resonator so as to transfer heat depending on compression and expansion of gas medium, and a high temperature heat exchanging portion formed at an end portion of the stack toward the acoustic generator so as to receive the heat transferred from the low temperature heat exchanging portion; a low temperature circulation line wherein one end of which is connected to the low temperature heat exchanging portion and the other end is connected to the fuel tank so as to transmit a low temperature circulation fluid cooled by the low temperature heat exchanging portion to the fuel tank; a low temperature heat exchanger installed within the fuel tank and connected to the low temperature circulation line so as to transfer heat within the fuel tank to the low temperature circulation fluid; a high temperature circulation line wherein one end of which is connected to the high temperature heat exchanging portion and the other end is connected to the canister 20, so as to send the high temperature circulation fluid heated by the high temperature heat exchanging portion to the canister; a high temperature heat exchanger installed to the canister and connected to the high temperature circulation line, so as to transfer heat of the high temperature circulation fluid to the canister; and a control unit controlling the acoustic refrigerator.
 2. The temperature control system of claim 1, further comprising a temperature sensor for detecting a temperature within the fuel tank and outputting a corresponding signal, and wherein the control unit controls the acoustic refrigerator on the basis of the signal of the temperature sensor.
 3. A temperature control system for a fuel tank of a vehicle, comprising: an acoustic refrigerator; a low temperature circulation line wherein one end of which is connected to the low temperature heat exchanging portion and the other end of which is connected to the fuel tank so as to transmit a low temperature circulation fluid cooled by the low temperature heat exchanging portion to the fuel tank; a low temperature heat exchanger installed within the fuel tank and connected to the low temperature circulation line so as to transfer heat within the fuel tank to the low temperature circulation fluid; a high temperature circulation line wherein one end of which is connected to the high temperature heat exchanging portion and the other end is connected to the canister, so as to send the high temperature circulation fluid heated by the high temperature heat exchanging portion to the canister; a high temperature heat exchanger installed to the canister and connected to the high temperature circulation line, so as to transfer heat of the high temperature circulation fluid to the canister; and a control unit controlling the acoustic refrigerator.
 4. The temperature control system of claim 3, wherein the acoustic refrigerator further comprises: an acoustic wave generator; a resonator for converting an acoustic wave generated by the acoustic wave generator to a standing wave; a stack disposed between the acoustic wave generator and the resonator; a low temperature heat exchanging portion formed at an end portion of the stack toward the resonator so as to transfer heat depending on compression and expansion of gas medium; and a high temperature heat exchanging portion formed at an end portion of the stack toward the acoustic generator so as to receive the heat transferred from the low temperature heat exchanging portion.
 5. The temperature control system of claim 4, further comprising a temperature sensor for detecting a temperature within the fuel tank and outputting a corresponding signal, and wherein the control unit controls the acoustic refrigerator on the basis of the signal of the temperature sensor. 